1. Field of the Invention
The present invention relates to a nozzle vane driving control apparatus of a variable nozzle turbocharger which is to be used in a diesel engine for a car, for example.
2. Related Art
For example, a stepping motor has been used as an actuator for carrying out a driving operation for opening and closing the nozzle vane of the variable nozzle turbocharger (for example, see JP-A-2001-107738, Pages 4 and 5, FIG. 1). An operating piece coupled to the stepping motor is operated so that a spindle is rotated to open or close each of the nozzle vanes of a variable nozzle through a link mechanism. Moreover, the driving operation of the stepping motor is controlled corresponding to the operating situation of an engine by an electronic control unit (ECU) and the flow velocity of an exhaust gas to be sprayed onto a turbine wheel is regulated.
In the conventional variable nozzle turbocharger, however, an actuator for opening and closing each of the nozzle vanes of the variable nozzle and an electronic control unit for controlling the driving operation of the actuator depending on the operating situation of the engine are separately attached to the turbocharger. Therefore, a large attachment space is indispensable. Correspondingly, the size of the whole turbocharger is increased and a weight is increased. Moreover, a cable for electrically connecting the actuator and the electronic control unit is to be provided under bad conditions of a high thermal environment. For this reason, it is hard to always maintain a durability and a responsiveness.